Javascript performance with closure

Question

var name = function(n) {
    var digits = [\'one\',\'two\',\'three\',\'four\'];
    return digits[n];
}

var namenew = (function() {
    digits = [\'one\',\'two\',\'thre         


        

Answer 1

The first function recreates digits every time it's executed. If it's a large array this is needlessly expensive.

The second function stores digits in a context shared only with namenew. Every time namenew is executed it only performs a single operation: return digits[n].

An example like this wont show any noticeable gains in performance, but with very large arrays/objects/function calls performance will be improved significantly.

In an OOP perspective using a closure in this manner is similar to storing data in a static variable.

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Don't forget that namenew is receiving the result of the closure function. The closure itself is only executed once.